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Evaluation of Sediment Transport Empirical Equations: Case Study of the Euphrates River West Iraq

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Evaluation of Sediment Transport Empirical Equations: Case Study of the Euphrates River West Iraq Arabian Journal of Geosciences (2021) 14:825 https://doi.org/10.1007/s12517-021-07177-1 ORIGINAL PAPER Evaluation of sediment transport empirical equations: case study of the Euphrates River West Iraq Sadeq Oleiwi Sulaiman1 & Nadhir Al-Ansari2 & Ahmed Shahadha1 & Rasha Ismaeel1 & Sura Mohammad1 Received: 7 December 2020 /Accepted: 23 April 2021 # The Author(s) 2021 Abstract Sediment transport in rivers is an important and complex process. It is very important to know the nature and quantities of sediments transported in course of rivers to achieve prudent water management. Due to the presence of most of the important projects on or near the banks of the river in the study area, so there is always a fear that these projects will be affected by the processes of erosion, transport, and sedimentation among the decision makers. Therefore, there is a need to develop our knowledge of the suitable equations that can be applied with acceptable accuracy to obtain satisfactory results for monitoring the processes of erosion, sedimentation, and transport that occur in River path to monitor and anticipate the changes taking place in the areas of the riverbanks. This study was carried out to check the reliability of different sediment transport formulas using data collected from the Euphrates River at the thermal power station in Al Anbar province, Iraq. The study also aimed to select the best formula for this site. Hydrological data have been collected. These were used for computing the total sediment load in the river at a specified cross-section using common sediment transport formulas ascribed to Ackers-White, Bagnold, Yang, Colby, Shen and Hung, and Engelund-Hansen. The performance of these formulas was assessed based on the accuracy of the predictions of the observed sediment load within a limited discrepancy ratio. The evaluations showed that the Engelund-Hansen formula represented the best formula for this river reach. Keywords Sediment transport . Bed load . Suspended load . Euphrates River . Sediment transport formulas Introduction sediment load is derived from the bottom and sides of the channel (Salih et al. 2020). Today, one of the major issues Most rivers are self-formed, or alluvial (Sui-ji and Jin-ren facing water resource managers is the impact of bed load 2002). The distinctive path is created by streams and alluvial and suspended sediment transport on the resident aquatic or- rivers mobilizing and transporting sediment. With regard to ganisms and quality of water (Tao et al. 2019). In addition, the alluvial channels, the width and depth of the channel reflect majority of construction activities near or in the watercourse the water flow as well as the nature of the material which have the potential to result in reduced stability of the adjacent makes up the channel boundaries. Typically, rivers running riverbanks and/or increasing the bed load and suspended sed- through soft material have high sediment loads in comparison iment transport, as well as turbidity. Generally, sediment to the rivers which are exposed to bedrock, since much of transport rates are divided into bed load, suspended sediment load. The suspended sediment load is sometimes further di- Responsible Editor: Broder J. Merkel vided to the suspended bed material load and the wash load. The wash load sediment is the fine grain-size fraction derived * Nadhir Al-Ansari from the catchment surface. The key difference between the [email protected] wash load and the suspended bed material and bed load is that the wash load is supply controlled whereas the latter are gen- Sadeq Oleiwi Sulaiman erally not supply controlled but controlled by the transport [email protected] capacity of the river. The wash load represents very fine sed- 1 College of Engineering, University of Anbar, Ramadi, Iraq iment particles transported in suspension by the flow. The transport law for wash load is, therefore, very different from 2 Civil, Environmental and Natural Resources Engineering, Lulea University of Technology, 97187 Lulea, Sweden that for bed load and the suspended bed material load (Khullar 825 Page 2 of 11 Arab J Geosci (2021) 14:825 et al. 2010). The rate of transport of wash load is considered to The process of erosion and sedimentation that occurs con- depend upon the supply rate from the upstream catchment and tinuously during the process of water flow along the this cannot be uniquely related to the hydraulic parameters of Euphrates River in the study area is a subject of great concern, the flow. While the transport of suspended bed material in especially after each release of high discharges from Haditha alluvial channels is typically assumed to be controlled by river Dam upstream of the study area. There are many industrial hydraulics and the sediment supply within the channel bed and commercial establishments built on or near the banks of and banks, the controls on wash load transport are likely to the river that will be affected in one way or another by the be more variable and complex. The wash load is supplied erosion, sedimentation, and transportation processes that take from upland catchment sediment sources and delivered to place in the river. Therefore, with the increase in the number the drainage network by overland flow during runoff pro- of projects on the banks of the river in the study area, which is duced by precipitation. Wash load sediment is highly mobile closely affected by the geomorphological dynamics of the and is not commonly deposited within the channel bed. The river basin, there is a need to develop our knowledge of the find of origin suspended sediment sources catchment is mechanisms of sediment transport and management and the attended by difficulty (Collins and Walling 2004). Most of equations that can be applied with acceptable accuracy to ob- the wash load material in the Euphrates River within the study tain satisfactory results for monitoring the processes of ero- area comes from the surface runoff after the heavy rainstorms sion, sedimentation, and transport that occur in River path to that fall on the catchments in the desert upstream of the study monitor and anticipate the changes taking place in the areas of area. The days during which the sediment samples were taken the river banks and the associated transport of pollutants and were not preceded by any rainfall; therefore, no presence of fertile along these banks. To the best knowledge of the current washing load material is expected among the suspended load research, in this study, sediment transport was calculated by materials. Because the study area is in an arid area and the applying several well-established empirical equations to the flow of the river is controlled by the Haditha dam which is Euphrates River. Moreover, many researchers use sometimes located about 130 km upstream of the study reach and traps numerical methods to simulate the flow of water and sediment the wash load of the river, wash load was excluded from the transport. Generally, the finite element (FE) approach proved measurement of total sediment load and ignored from calcu- to be a robust approach that has been used by many re- lations (Khullar et al. 2010; Mustafa et al. 2017; Walling and searchers to evaluate not only sediment transportation but oth- Collins 2016; Yuill and Gasparini 2011). Most sediment er geotechnical applications as well (Alimohammadi et al. transport equations are obtained assuming that the sediment 2021a, b;Ferrarinetal.2008); however, this approach is out transport rate can be determined from the dominant hydraulic of the scope of this research. The goal of this study was to variables (Afan et al. 2016). Because of the lack of consisten- provide decision makers and hydraulic engineers with an ac- cy of the assumptions involved, compatibility is often poor curate and reliable sediment transport equation that can be when such equations are applied for flow conditions different applied for designing the river morphological aspects and riv- from those for which they were developed. The calculated er engineering management. rates of sediment transport often differ from each other and from measured (Sharafati et al. 2019). The commonly used sediment transport functions include those developed by Yang Study site (1973), Colby (1960), Ackers and White (1973), Bagnold (1956), Shen and Hung (1972), and Engelund-Hansen The study reach for this research is the part of the Euphrates (1967) (Ackers and White 1973; Engelund and Hansen River opposite Al Anbar thermal power plant, which is locat- 1967;Mays2010; Mustafa et al. 2016). The transport of sed- ed in the west of Iraq in Al Anbar province, northwest of the iment in the Euphrates River within the Iraqi borders has been city of Ramadi at longitude (43° 01′ 17″) and latitude (33° 32′ studiedbymanyresearcherswhohaveestimatedthe 11″). This area is considered to be one of the important areas suspended sediment and the bed load at a number of sites on of the sedimentary plain through which the Euphrates River the Euphrates River. The accuracy of the results reflects field passes, Fig. 1 (Al-Mimar et al. 2018;Najmetal.2020). The data available for bed load calculation and the reliability of the location was developed as a type of thermal power plant, suspended load measurements. Some researchers have devel- where the station works by burning fuel such as heavy oil, oped relationships with the sediment transport depending up- creating high-temperatures, and high-pressure steam; such on the amount of discharge passing through the river. The steam was applied to drive a steam turbine, which drives the annual sediment load passing through the Euphrates River power generator. The thermal power plant withdraws water within Al Anbar province for various studies was estimated from the Euphrates River through the intake upstream of the to be between 1.9 * 106 tonne/year and 2.1 * 107 tonne/year plant at a flow rate of up to 90 m3/s when operating the plant at (Al-Ansari et al.
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